An ultrasonic sensor includes a reception electrode to receive a voltage generated by a piezoelectric layer and the voltage is generated by the piezoelectric layer according to an ultrasonic wave. Generally, the reception electrode is electrically coupled to the piezoelectric layer via a conductive film in an edge area of the ultrasonic sensor. However, due to a high surface tension of the piezoelectric layer, the conductive film usually misses a part in an edge of the conductive film.